So, you are invited to a dinner by extraterrestrial hosts. Do you accept the invitation? And if so, which foods and beverages would be safe to eat? And, could you actually live long term on ET food? Or the other way around, if you have an ET guest, what food could you safely serve for them to eat?
First, it's not likely that you would enjoy a dinner served in a sauce of liquid nitrogen or liquid methane :). So, let's assume that they are organic carbon based lifeforms from an Earth-like world or at least an environment with Earth type temperatures and conditions (including perhaps living in oceans of icy moons).